A support of the previously mentioned kind, which is known from the state of the art, has the advantage by way of the counterweight the utility load can be exactly compensated so that it is possible to force free move and to position the utility load in space. A disadvantage, however, is that with this system the utility load can only be positioned on a spherical surface. This for many applications is a relatively strong spatial limitation.
Further known are ceiling mounted support systems for the positioning of a utility load, such as for example an apparatus, a lamp or the like, comprising a ceiling connector, a supporting arm and a swing arm, at the free end of which the utility load hangs. The ceiling connector is rigidly fixed to the room ceiling by screws to absorb the forces and moments resulting from the utility load. These moments may be considerable depending on the utility load and the maximum effective radius, and are determinative for the choice of the degree of rigidity. The supporting arm is connected to the ceiling connector by a joint for swinging movement about the vertical axis. The remote end of the supporting arm carries a second joint rotatable about the vertical axis, to which for example the spring arm is connected. The spring arm includes a connector arm which from a horizontal position can be swung upwardly and downwardly about a first horizontal axis. At the end of the connector arm the connector arm is connected to the utility load, for example by way of a joint lying parallel to the connector arm. The vertical component of the swinging movement of the connector arm creates a height adjustment of the utility load with a spring delivering a counter force to the weight force, so that in each height position a stable weight compensated position is achieved. The horizontal portion of the connecting arm can execute a circular movement about the second rotation joint. In combination with the rotating movement about the first vertical rotation joint it is possible to reach each point of a horizontally lying circular surface, so that in cooperation with the up and down movement the utility load can be positioned at any point inside of a cylindrical space (more exactly: a barrel-shaped) space. Since in the realized construction no complete compensation of the weight force by way of a spring is achieved, the support system must be provided with friction in order to assure stability in the chosen position. This friction must be overcome by the user with each adjustment procedure.